


Science and Logic

by Jestana



Series: AU_Bingo [3]
Category: Sherlock Holmes (2009)
Genre: Alternate Universe - Police, F/M
Language: English
Status: Completed
Published: 2010-12-22
Updated: 2010-12-22
Packaged: 2017-10-13 23:15:45
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,914
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/142780
Author URL: https://archiveofourown.org/users/Jestana/pseuds/Jestana
Summary: <blockquote class="userstuff">
              <p>A serial rapist/killer has all of Scotland Yard stymied, including their best detective: Sherlock Holmes.</p>
            </blockquote>





	Science and Logic

**Author's Note:**

> Written for au_bingo on LJ for the prompt _Other: Police_. Warning for risqué discussions and references to rape. Inspired by [this](http://midnight-city.livejournal.com/79982.html) fanart of the 2009 film. My apologies in advance if there are any glaring Americanisms. I did my best. _This was written before I'd even heard about the modern take BBC was doing. This is all out of my own brain._ Beta by unicorn_catcher and umbralillium.

**Science and Logic**

  
"So, Dr Watson, what's the status of our Jane Doe?" DSI George Lestrade asked, striding into the morgue as he asked the question.

John Watson hardly looked up from his work. "She's certainly our latest victim in the serial killer case. She has the same post-mortem bruising around her wrists and ankles, the same ligature marks around her neck--"

"What about the rape kit?" A different voice asked from the doorway. "Have you run that yet?"

A brief glance took in a familiar tousle-haired, sloppily-clothed figure lounging against the door jamb. "Just about to do that, Holmes. Thank you for trying to do my job for me."

"Not at all, Watson." DS Sherlock Holmes sauntered over to the examination table.

Lestrade, sharply dressed in his usual dark suit and tie, hair neatly combed, and face clean-shaven, made a striking contrast to Holmes in his wrinkled trousers, half-tucked shirt, uncombed hair, and stubble-covered jaw. "Well, well, nice of you to actually grace the station with your presence, Holmes. You _do_ realise that your shift started two _hours_ ago, right?"

"Did it?" Holmes asked, grey eyes wide with feigned surprise. "Fancy that, Watson: Lestrade can tell time. Who'd have thought?"

Watson kept his eyes on his task, certain he would laugh if his friend managed to catch his eye. "Leave me out of this, Holmes."

"If you didn't have such a good solve rate..." Lestrade growled at Holmes. His next statement he addressed to Watson. "Let me know if you find something."

Before the Detective Superintendent could take more than two steps, Watson replied, "Actually, I think I did."

"What?" Holmes straightened up from his usual slouch and Lestrade turned back. "You mean besides evidence of sexual trauma and traces of latex?"

Watson nodded, carefully documenting the slide he held. "Yes. The condom our killer used must have had a hole because this--" he held up the slide for both of them to see "--is seminal fluid."

"That's just the break we need," Lestrade breathed, relief more than evident in his voice.

Watson finished and placed the slide in an evidence bag. He then handed it off to his assistant, Dr. Clarkston, who left to take it up to the lab for processing. "Well done, Watson."

"Thanks, Holmes." The coroner turned to begin reconstituting the body. He wasn't surprised to see that Lestrade had already left. The inspector had always been squeamish about cutting up corpses. "You know, you should at least _try_ to get along with Lestrade. He _is_ your boss, you know."

Holmes watched Watson work in silence for several moments, his expression meditative. "Why should I? He's an idiot."

"That doesn't give you the right to insult him," Watson answered mildly, sewing up the Y-incision. "You're going to eventually push him too far."

Holmes shrugged, half-perching on the stairs that led down to the autopsy bay. "Then I'll become a private detective. At least then I could pick and choose my cases."

"You mean you don't do that _now_?" Watson looked up at his friend with a greatly exaggerated expression of surprise before he moved to sew the skull cap back in place. "Call the presses and inform them that Sherlock Holmes takes _every_ case assigned to him."

The detective watched the coroner tie off the last stitch. "You should be a stand-up comic. Everyone would love your jokes."

"You'd miss me too much," Watson retorted, removing his latex gloves and tossing them in the bin with the other used gloves.

Holmes followed Watson over to his workstation and leaned against the partition. As the brunette began to type, the dark-haired man muttered, "Mary would miss you, too."

"We're just friends, Holmes," Watson stifled a sigh. This was an old argument: Holmes insisted that she was attracted to Watson while the coroner insisted she wasn't. "Unlike you and a certain partner of yours. Don't think I don't know that you two used my examination table for one of your assignations."

Holmes looked up with an obnoxious leer. "At least we've _acted_ on our attraction."

"I _knew_ I'd find you down here, Sherlock!" A familiar female voice rang out across the morgue. "Get your gorgeous arse moving. We got a hit on the DNA evidence."

Watson rolled his chair back so he could look past Holmes to see not only DS Irene Adler standing in the doorway, but Forensic Specialist Mary Morstan as well. The former had her curly black hair pulled back into a loose ponytail, wearing an oxford shirt that revealed far too much cleavage tucked into a pair of tight trousers held up by suspenders that Watson was pretty sure had originally belonged to Holmes. The latter, on the other hand, had her golden blonde hair pulled back into a sensible bun, wearing a white lab coat over a properly-buttoned blouse, and trousers. Holmes responded to his partner's jibe as he turned to face the two women, "How did we get a hit so fast?"

"The unknown donor is a partial match for Henry Blackwood," Mary explained, pushing her wire-frame glasses up the bridge of her delicate nose.

Watson frowned and stood up, casually reaching up to brace himself on the partition when his leg protested the movement. "Isn't he the schoolteacher who was accused of statutory rape a couple years ago?"

"Yes, but the DNA tests came back negative," Holmes almost growled the words. One of Holmes' first cases as a detective, it was the only blemish on his otherwise-sterling record and a sore spot for him.

Irene tossed Holmes' battered sport coat to him. "Let's scoot, partner. He has a couple brothers, so maybe one of them is the one we're looking for."

"Stop nagging me, woman." Holmes shoved his arms into the sleeves of his coat and followed his partner from the morgue.

Mary turned to Watson once the sound of their friends' voices had faded. "Are you busy?"

"No, I just have paperwork," Watson replied, wondering why she'd asked. _Could Holmes be right?_

Hesitantly, pushing her glasses up the bridge of her nose again, she asked, "Would you like to go get a bite to eat? We don't have anything for a case right now."

"Yeah, food sounds good, actually," Watson agreed with a smile. He grabbed his walking stick from where it leaned against his desk and gestured for Mary to precede him from the morgue. "After you."

* * *

  
"Mary, Mary, quite contrary, how does your garden grow?" Irene's sing-song voice preceded her appearance at Mary's workstation.

Without missing a beat as she typed up her last report, Mary replied, "With processed samples and test results all in a row."

"That's a good one." Irene grinned and set the case with the test swabs on Mary's workbench. "More samples to test."

The blonde nodded and clicked the submit button for her report. "For the Blackwood brothers?"

"And sons," the dark-haired woman added, perching on a nearby stool as Mary opened the case to begin documenting the arrival of each swab. "Between the three brothers, they have six sons."

Mary stifled a sigh and simply nodded, ensuring each swab was carefully stored and ready to be processed. "I'll do them first thing in the morning."

"Fair enough." Irene hopped down from her stool when Mary retrieved her purse from its drawer in her desk. She'd already exchanged her lab coat for her jacket when she'd sat down to fill out her reports. "Are you off now?"

Mary nodded, eyeing her friend when the other woman exited the workstation with her. "Why do you ask?"

"I thought you'd like some company." Irene's face was the picture of innocence as they walked down the corridor to the bank of lifts.

The forensic specialist stopped, folding her arms across her chest. "What's going on?"

"Nothing's going on." The detective offered her most charming smile, the one that disarmed others and led them to underestimate her.

It didn't work on Mary. She'd known the other woman too long to be disarmed. "Normally you'd be off to find Sherlock so you two can boink each other in a broom closet, not offering to keep me company." She remembered something else before her friend could say anything. "John wasn't himself at lunch, either. If I were given to paranoia, I'd think there was some sort of conspiracy going on."

"Maybe he's finally realised how beautiful you are," Irene suggested with a playful grin.

The blonde scoffed, giving the dark-haired woman a look that suggested she was mental. "If either of us is beautiful, that's you. I'm merely pretty."

"Don't sell yourself short, Mary." Irene took her arm and gently urged her to continue walking. "You have a classic, understated beauty that draws men in instead of hitting them over the head."

Mary laughed, allowing herself to be urged into walking again. "Is that the sort of beauty _you_ have? The kind that hits men over the head?"

"Naturally." The black-haired woman took a moment to preen, briefly reminding the blonde of a peacock as they reached the lifts.

Once they'd entered the one that opened the moment they'd hit the button, the forensic specialist commented, "I'm still not convinced that nothing's going on."

The detective sighed. "I don't know if you've seen pictures of the victims the serial killer, but they're all around your height, build, colouring, and age."

"So you're worried that I might become one of the victims." Mary inferred, arms folded across her chest once more.

Irene nodded, her expression unusually serious. "Sherlock noticed the pattern first. He spoke with John and they asked me to warn you. Don't go anywhere alone."

"I'm not helpless," the blonde retorted, stung that the others discussed this without her. "My father was on the police force for years before the bullet he took in the spine forced him to retire early. My brother was in Iraq with John. Both of them made sure I can defend myself against someone larger and stronger, armed or not."

Surprisingly, the black-haired woman smirked. "I know. Sherlock was quite shocked when you took him down. He didn't expect you to fight so well."

"Which just proves my point," Mary answered pointedly. "This isn't the Victorian period where women were expected to stay at home and let their husbands fight their battles."

Irene shook her head with a sigh. "This man catches his victim off-guard. John found traces of chloroform in every victim's respiratory tract. Depending on how much was used, you'd be knocked out before you could realise you were in any danger. You have to see your opponent coming in order to defend against him."

"Just because I _fit_ the victim profile doesn't mean I'm going to _be_ one," she snapped as the lift came to a stop, feeling distinctly ruffled. "Good night."

Mary could feel Irene's eyes on her as she stalked towards her car. When she glanced back at the lifts, though, her friend had already left.

* * *

  
Holmes watched with annoyance as the house of business cards he'd been building collapsed under the folder Irene tossed on his desk. He looked up at his partner with a scowl. "Was that necessary, Woman?"

"We got our results back from the lab," she answered, unfazed by his scowl. "None of the Blackwood men are full matches for the perp. They're all partial matches."

He seized the folder and flipped it open, flicking through the papers inside. "Did Mary double-check the results?"

"Mary didn't process the samples." Irene sounded tired. "She didn't come in at all today."

Holmes deliberately hid the worry he immediately felt. "Maybe she's not feeling well."

"I called her mobile and it went right to voice mail." Out of the corner of his eye, he saw her rub her temples. Both of them knew that could be bad or good. "She doesn't have a phone in her flat, either, because she didn't see the point when she already has her mobile."

He closed the folder and set it on his desk. With his eidetic memory, he'd already memorised all the information it contained. "Did you call her landlord?"

"The landlady said Mary never came home last night." Irene let her hands fall into her lap, idly spinning her chair back and forth. "She didn't worry, though, because she thought Mary had gone home with a 'nice young man'."

Watson arrived just then, light brown hair unusually dishevelled with new lines of worry around his eyes and mouth. " _When_ did Mary go missing?"

"Sometime after leaving work last night," Irene answered, as unsurprised as Sherlock that the coroner was worried about the forensic specialist. He was smitten with her, even if he hadn't realised it yet. "I watched her walk to her car."

Holmes leaned forward in his chair, grey eyes keen. "Did you watch her get into her car and drive off?"

"Well, no." Irene sat up, blue eyes narrowing as she realised where Holmes was going with his question. "Perhaps something is there."

The two detectives hurried from their office, closely followed by Watson. When they arrived, they found Mary's car still where she'd parked it the day before, her purse spilled out on the ground, mobile phone a crushed wreck beside it. "Well, that's why my calls went to voice mail."

"We need more data," he reminded his partner as Watson finally caught up with them.

The coroner watched as the partners split up to search around the car, taking opposite directions from Mary's purse. Holmes trusted that his flatmate would know better than to even nudge it with his cane. Until they could confirm that no foul play was involved-- unlikely --it would be kept as evidence. "We should have done more to protect her."

"You're not to blame, John," Irene called from a rather dark corner of the parking garage. "If you're going to blame anyone, you should blame _me_. I didn't stay to make sure Mary got in her car safely--"

"She did, actually," Holmes interrupted, having reached the driver's door. "Or someone did."

Watson moved around the car to see what Holmes was looking at: the keys were in the ignition and there were signs of a struggle. "We'd better call it in."

As the coroner moved away to do that, Irene joined her partner, muttering, "I _told_ her he could still get her if he was devious enough."

* * *

  
Irene stood with Sherlock outside the interrogation room, watching Henry Blackwood and his lawyer, James Coward, run Lestrade in circles. Frustrated, the DSI got up and left the room. "I sure hope you two have ideas, because I can't justifiably hold him on the strength of a cigarette butt near a car."

"And even the connection between him and the butt is tenuous at best," Irene admitted, tugging fretfully at the ends of her hair. If only the two men weren't so calm, so collected!

Sherlock, who'd been muttering and pacing in the small space provided by the room, stopped suddenly and turned to face them. "Chimera!"

"'A thing of immortal make, not human, lion-fronted and snake behind, a goat in the middle, and snorting out the breath of the terrible flame of bright fire'," Irene responded almost without thinking. They sometimes challenged each other with obscure references, but usually only when they didn't have anything else to do. "What are you getting at, Sherlock?"

He gave her an admiring glance. "A word-perfect quote, my dear, but not what I meant."

"What _did_ you mean, then?" Lestrade demanded, sounding frustrated.

Instead of answering his question, Sherlock turned and picked up the file they had on Blackwood from the statutory rape case. Opening it up, he flipped through the pages and nodded to himself. "The DNA sample for the comparison test was taken from Blackwood's mouth."

"Yes, that's standard procedure." The lean, ferret-like man looked exasperated. "What of it?"

Sherlock closed the file and looked at Irene. "He was one of the first offspring created through in vitro fertilisation. What if more than one of the fertilised eggs _had_ survived the process?"

"Blackwood was a single birth," Irene countered, folding her arms across her bosom. "Unless something happened to the other egg, that's not possible."

A devious smile curved Sherlock's lips. "Something _did_ happen to the other egg: it was absorbed by Blackwood."

"Oh!" Irene stood up from her perch on the table edge, remembering the research Holmes had shown her. "Chimera!"

Lestrade interrupted them, looking very angry now. "What the bloody hell are you two going on about?"

"It's possible that Blackwood has a condition called tetragametic chimerism," Irene explained while Sherlock pulled out his mobile to make a phone call. "It happens when two different ova are fertilised by two separate sperm, only for the two fertilised eggs to fuse together into a single fertilised egg, usually at the zygote or blastocyst stage. This would result in the baby having two sets of DNA."

She looked up as Sherlock closed his mobile, a satisfied smile on his face. "Watson is coming in. He said there's a way to determine the possibility of chimerism without a DNA test. Once we've determined that, we can rightfully request a sperm sample."

"So you're telling me that we could take skin samples from two different parts of his body, and they could come up as two different donors?" their supervisor enquired, his voice rife with disbelief.

Irene nodded patiently. "It's conceivable, provided John finds what he's looking for."

"They're called Blaschko's lines," John's voice offered from the doorway. Irene was surprised to see that the coroner looked even more strained than he had been earlier, leaning heavily on his walking stick. "We all have them, but they're invisible in most people. Chimerism makes them visible to the naked eye."

Sherlock reached up and briefly squeezed his friend's shoulder. "Where are they located?"

"They form a 'V' shape along the back, 'S' shaped whorls on the chest, stomach, and sides, and wavy shapes on the head." John gestured with his hands as he described the shapes.

After a few moments of thought, Sherlock commented, "Well, his hair would hide shapes on the head, but we can probably get him to remove his shirt somehow."

"We could ask him to take it off," Lestrade suggested after a few moments' silence.

Before Sherlock could offer a scathing retort that would likely insult and belittle the rat-faced DSI, Irene replied, "No, I have a better idea. Excuse me, gentlemen." She left the room and got two cups of piping hot tea from the vending machine. Making sure the lids were loosely secured, she entered the interrogation room. "Sorry to keep you waiting, Gentlemen. I thought you'd like tea while you were waiting."

"No, thank you." Blackwood waved his hand dismissively, not that she was surprised. The black-haired man had been largely quiet during the interrogation, letting his lawyer speak for him.

Coward held up his hand. "Yes, something to drink sounds good."

Irene nodded and, as she approached to give the lawyer his tea, she tripped, spilling the hot tea all over Blackwood's back. He jumped to his feet, already unbuttoning his shirt. "You idiot!"

"I'm so sorry!" Irene offered her most sincerely apologetic look as Blackwood slid off his shirt. "I'll go get you something else to wear."

She hurried from the interrogation room and into the observation room. John had one of his scrub shirts ready. "Those are Blaschkoe's lines all right."

"Excellent!" Lestrade looked triumphant as he walked with Irene into the interrogation room. "I'm sorry about my detective's clumsiness, Mr Blackwood."

"Here's your shirt, sir," she added, offering him the scrub shirt meekly.

His expression distasteful, Blackwood took the shirt and pulled it on. "Are we done here?"

"Not quite," Lestrade replied. "If you don't mind, we'd like you to provide us with a sperm sample before you go."

From her position near the door, Irene saw Blackwood clench his hands into fists under the table. They had him!

* * *

  
"Mary!" Watson couldn't contain the shout that burst from him when he saw Irene helping Mary out of Blackwood's warehouse on the Thames early the next morning. He'd wanted to go in with the detectives and the uniformed officers, but Lestrade, Holmes, and Irene had all said no. He just didn't have the same training they did. He just had to trust the others to find Mary and get her out safely.

She must have heard him because she looked around at the sound of his shout and waved when she saw him. Irene said something to Mary that must have been cheeky judging by the detective's grin and the way the forensic specialist blushed in response. The two women made their way over to where the coroner waited. "She's a little bruised and scraped, but safe."

"Thank you, Irene." Watson smiled, blushing a little when she stretched up to kiss his cheek. She turned and whispered something to Mary before leaving to resume her duties. He cleared his throat, turning to the blonde. "Are you all right, Mary?"

Mary smiled faintly as he led her over to sit on the bumper of the ambulance. "I believe it's your job to determine that."

"Perhaps I should have asked how you're feeling first," he commented with a nervous chuckle, examining the scrape he found on her forehead just below the hairline.

She flinched as he carefully cleaned the scrape. "It's just as Irene said: scraped and bruised, but otherwise fine. Blackwood didn't really do anything except tie me up."

"So I see." Watson had pushed the sleeves of her jacket up to see the marks on her wrists where the ropes had dug into the skin. He clenched his jaw at the thought of Blackwood laying even a finger on her.

Mary's hands trembled as he tended to her wrists, her voice soft as she told him, "He tied my ankles, too."

He nodded as he finished wrapping bandages around her wrists. "Your socks should have protected your ankles."

"Not when he took them off before he tied me up," she responded quietly.

Watson glanced up at her, surprised, and knelt to lift the legs of her trousers. There were angry red marks around her ankles above her sensible shoes. "That bastard..."

"He won't be able to hurt anyone ever again, John," Mary reminded him gently as he tended to her ankles. "That's what counts."

He nodded, wrapping the bandages around her ankles. "Yes, but I don't like the idea of him hurting you even a little."

"Why? Because I'm your friend?" Her voice was quiet as he put away the items he hadn't used in the medical kit.

Watson stared at her bowed head, realisation slamming into him with force of an explosion. She was more than a friend to him. She was the woman who held his heart, though he hadn't even noticed she'd stolen it from him. Reaching down, he gently tipped her head up so her brown eyes met his hazel ones. "No, it's because you're the keeper of my heart."

"Do you mean it?" she asked, her eyes wide with hope and fear. "You're not saying it because Irene and Sherlock have been dropping hints about my feelings for you?"

Smiling, he leaned down to brush a light kiss across her lips. "I mean it, Mary. I love you."

"I love you, too," she whispered just before she pulled him close for a proper kiss.

 **End**


End file.
